Latest / Daniel and Kelly’s Extraordinary Universe / What’s the largest asteroid impact in Earth’s history?

Transcript

What’s the largest asteroid impact in Earth’s history? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Daniel. It's great to be talking to you today. So
• 0:11
  Speaker 1: now I would love for you to go ahead and
• 0:13
  Speaker 1: reassure me that today we're not going to be talking
• 0:16
  Speaker 1: about how scary and dangerous the universe is.
• 0:21
  Speaker 2: Oh no, no, not at all. Well, I mean maybe
• 0:23
  Speaker 2: a little bit.
• 0:24
  Speaker 1: Uh, Daniel, that is clearly hedging. I'm gonna need more clarity.
• 0:29
  Speaker 2: I mean, we're only going to talk about scary and
• 0:32
  Speaker 2: dangerous family destroying things that already happened in.
• 0:35
  Speaker 1: The past because we have some way to prevent these
• 0:39
  Speaker 1: scary and dangerous things from happening in the future, like
• 0:42
  Speaker 1: to my children. Right, no comment, dude, not okay, totally, totally,
• 0:51
  Speaker 1: not okay.
• 0:52
  Speaker 2: You got to embrace the danger, Kelly. That's where the
• 0:54
  Speaker 2: thrill is.
• 0:55
  Speaker 1: I I guess I'm pushing through one way or another.
• 1:00
  Speaker 1: So let's do this just another show my kids won't
• 1:03
  Speaker 1: listen to.
• 1:19
  Speaker 3: Hi.
• 1:19
  Speaker 2: I'm Daniel, I'm a particle physicist and a professor at
• 1:22
  Speaker 2: UC Irvine, and I'm looking forward to the destruction of
• 1:25
  Speaker 2: the Earth.
• 1:26
  Speaker 1: I'm Kelly Waitersmith, adjunct faculty at Rice University, and I'm
• 1:31
  Speaker 1: looking forward to yet another episode filled with existential dread.
• 1:37
  Speaker 2: You know in those moments as the Earth is being
• 1:40
  Speaker 2: obliterated by some huge impactor, We're going to learn a
• 1:43
  Speaker 2: lot about how the Earth is put together and what's
• 1:45
  Speaker 2: inside of it. And as all those insides come to
• 1:48
  Speaker 2: the outsides.
• 1:49
  Speaker 1: You know, I'm going to hope that in that moment
• 1:53
  Speaker 1: we all stop worrying about the details and we just
• 1:56
  Speaker 1: hug our kids and our dogs and stuff. But I'm
• 1:59
  Speaker 1: sure the physicists we'll still be collecting data, and the
• 2:01
  Speaker 1: economists will be quantifying something, and anyway, well.
• 2:05
  Speaker 2: We are all still live and wondering about the universe.
• 2:08
  Speaker 2: And so welcome to the podcast Daniel and Jorge Explain
• 2:11
  Speaker 2: the Universe, a production of iHeartRadio in which we do
• 2:15
  Speaker 2: our best to understand the nature of the universe before
• 2:18
  Speaker 2: it comes crashing down on us. We try to cast
• 2:21
  Speaker 2: our minds out into the deepest, darkest reaches of space
• 2:24
  Speaker 2: and understand what's out there, how does it all work.
• 2:27
  Speaker 2: We look back into the history of the universe to
• 2:30
  Speaker 2: understand where it all came from, how it all works,
• 2:32
  Speaker 2: and how we got to be where we are. Jorge
• 2:35
  Speaker 2: can't be with us today, but I'm very glad to
• 2:37
  Speaker 2: have with us. Kelly. Kelly, thanks for joining us on
• 2:39
  Speaker 2: another adventure of dangerous history of the universe.
• 2:44
  Speaker 1: Thanks for having me. Despite what it might sound like,
• 2:46
  Speaker 1: I really do enjoy these episodes.
• 2:51
  Speaker 2: And there is a lot of danger out there in
• 2:54
  Speaker 2: the universe. If you cast your telescopes up to the Moon,
• 2:57
  Speaker 2: for example, you see that the surface is riddled with craters.
• 3:01
  Speaker 2: It looks like it's survived a drive by asteroiding. And
• 3:05
  Speaker 2: if you look even further out into the Solar System,
• 3:07
  Speaker 2: you can see crazy things like comets smashing into Jupiter,
• 3:11
  Speaker 2: creating fireballs the size of Earth. All this kind of
• 3:14
  Speaker 2: stuff seems to be happening all over the Solar System.
• 3:17
  Speaker 2: It's a dangerous place, epic and that might make you wonder,
• 3:20
  Speaker 2: of course, how safe is our home here? Is the
• 3:24
  Speaker 2: plan be strategy for a planet Earth super important? Do
• 3:26
  Speaker 2: we need to scramble to get off of Earth before
• 3:29
  Speaker 2: something comes and obliterates us. One way to answer that
• 3:32
  Speaker 2: question is to think about our cosmic history. Of course,
• 3:35
  Speaker 2: we'd like to know what might be hitting us in
• 3:37
  Speaker 2: the future, but the best way to learn about that
• 3:39
  Speaker 2: might be to think about things that have already hit
• 3:42
  Speaker 2: us in the past.
• 3:44
  Speaker 1: Are you going to be making me a question? The
• 3:46
  Speaker 1: conclusions from my book that maybe we do need that
• 3:51
  Speaker 1: Plan B and we need to start today because our
• 3:54
  Speaker 1: demise is imminence.
• 3:56
  Speaker 2: Maybe, or you could also look at this history and say, hey,
• 3:58
  Speaker 2: we survived all this stuff, so maybe it's not such
• 4:01
  Speaker 2: a big deal.
• 4:02
  Speaker 1: Right, all right, Well, let's see where this goes.
• 4:06
  Speaker 2: And so today on the podcast, we're going to be
• 4:07
  Speaker 2: diving deep into the history of Earth to answer the
• 4:10
  Speaker 2: question what is the largest asteroid impact in Earth's history?
• 4:20
  Speaker 1: You know who has a big impact. Your listeners, Let's
• 4:27
  Speaker 1: hear what they have to say.
• 4:29
  Speaker 2: Thanks very much to everybody who volunteers for this audience
• 4:31
  Speaker 2: participation segment of the podcast. We really love hearing your voices.
• 4:36
  Speaker 2: It helps us calibrate the level of the podcast. Plus,
• 4:39
  Speaker 2: we love you guys. We want to hear your voices
• 4:41
  Speaker 2: and we hope you enjoy hearing your own voice on
• 4:43
  Speaker 2: the podcast. If you'd like to play for a future episode,
• 4:46
  Speaker 2: don't be shy. Write to me two questions at Danielandjorge
• 4:50
  Speaker 2: dot com. Here's what listeners had to say. Wasn't just
• 4:54
  Speaker 2: the asteroid that made the dinosaurs extinct? Almost meaning?
• 5:00
  Speaker 4: Was it thea the planetoid that theoretically smashed into the
• 5:06
  Speaker 4: Earth and kind of blew them both apart and became
• 5:09
  Speaker 4: the Moon. I saw a model recently that looked so
• 5:12
  Speaker 4: beautiful of kind of this orange fluid, two spheres banging
• 5:17
  Speaker 4: into each other, and then the Moon forming, So maybe
• 5:20
  Speaker 4: it was that one.
• 5:21
  Speaker 3: I think that there's remnants of an ancient impact crater
• 5:24
  Speaker 3: in Europe somewhere, or maybe South America.
• 5:27
  Speaker 2: I can't really remember.
• 5:29
  Speaker 3: From memory. There was a very large asteroid impact in
• 5:33
  Speaker 3: South America somewhere that closed one of the dinosaur extinctions,
• 5:37
  Speaker 3: but I can't remember what its name is. Well, alternatively,
• 5:42
  Speaker 3: could the moon the collision that created the Moon be
• 5:45
  Speaker 3: the largest impact that the Earth has they've experienced. I
• 5:48
  Speaker 3: don't know whether that counts as an asteroid, but maybe
• 5:51
  Speaker 3: the first one.
• 5:52
  Speaker 5: That comes to mind disaster that killed the dinosaurs, though
• 5:54
  Speaker 5: I guess that was only like sixty five million years ago.
• 5:58
  Speaker 5: Since the Earth has been around for I think billions
• 5:59
  Speaker 5: of years are probably many more, much larger than that
• 6:02
  Speaker 5: earlier on. I guess another idea might be whatever it
• 6:05
  Speaker 5: was that hit the early proto Earth and split off
• 6:08
  Speaker 5: into the Moon.
• 6:09
  Speaker 6: Well, the extinction event of the dinosaurs comes to mind
• 6:13
  Speaker 6: up top, but probably there was a larger collision when
• 6:16
  Speaker 6: the planet was still pretty squishy. Probably there was a
• 6:20
  Speaker 6: larger one there, my best guess.
• 6:23
  Speaker 1: So one thing that I thought was interesting about the
• 6:26
  Speaker 1: responses is that I think there was a bit of
• 6:28
  Speaker 1: reticence to answer because folks weren't certain that they had
• 6:31
  Speaker 1: the difference between asteroids, meteors, comets meteorites clear. Should we
• 6:37
  Speaker 1: quickly go over like which ones and clarify that we're
• 6:41
  Speaker 1: specifically talking about asteroids today or do you think we
• 6:43
  Speaker 1: don't need to go over that.
• 6:45
  Speaker 2: No, I'm always down for exploring the ridiculous naming systems
• 6:49
  Speaker 2: in physics.
• 6:52
  Speaker 1: Or is today's episode just like giant hunks of stuff
• 6:55
  Speaker 1: and we're being general?
• 6:57
  Speaker 2: I mean, from a physics point of view, it doesn't
• 6:59
  Speaker 2: really matter. It's giant hunks of stuff hurtling themselves towards
• 7:02
  Speaker 2: the Earth that created huge explosions and left marks on
• 7:05
  Speaker 2: the Earth's surface. But it does kind of matter where
• 7:07
  Speaker 2: those things came from if you want to think about
• 7:08
  Speaker 2: our future prospects and whether, for example, your children will survive.
• 7:12
  Speaker 1: And I do care about that because I'm not a physicist,
• 7:16
  Speaker 1: And so what's the difference between an asteroid, a comet.
• 7:20
  Speaker 2: And a meteor yeah, great question. So an asteroid is
• 7:24
  Speaker 2: basically a small rock that orbits the Sun. These things
• 7:27
  Speaker 2: are smaller than a planet if they're like bigger than
• 7:30
  Speaker 2: the pebble sized objects that are called medioroids. So asteroids
• 7:34
  Speaker 2: are bigger than meteoroids, but smaller than planets. And it's
• 7:38
  Speaker 2: also the distinction that planets have to like clear the
• 7:40
  Speaker 2: path they're in. So you can have like a bunch
• 7:43
  Speaker 2: of asteroids in like a ring around the Sun and
• 7:46
  Speaker 2: that's not an issue. But nothing in there can basically
• 7:48
  Speaker 2: be a planet, even if it's as big as a planet.
• 7:52
  Speaker 2: So there's a complicated distinction there between like planets, dwarf planets,
• 7:56
  Speaker 2: asteroids and meteoroids. And then of course there's comets.
• 8:00
  Speaker 1: Okay, but it's mostly all just a matter of size.
• 8:02
  Speaker 2: It's mostly a matter of size. Comets actually come from
• 8:04
  Speaker 2: a different place that come from deeper in their Solar system.
• 8:07
  Speaker 2: There's either the Kuiper Belt or the Ort Cloud for
• 8:10
  Speaker 2: really distant stuff, and we'll talk about that a little bit.
• 8:13
  Speaker 2: So that's asteroids and meteoroids and comets. Those are all
• 8:17
  Speaker 2: things out in the Solar System. A meteor is something
• 8:20
  Speaker 2: that's burning up in our night sky, something that hits us,
• 8:25
  Speaker 2: and so that can be an asteroid or a comet
• 8:27
  Speaker 2: or a little bit of alien space junk or whatever.
• 8:30
  Speaker 2: So meteor is basically when it hits the Earth, asteroid,
• 8:34
  Speaker 2: meteoroid in comet is when it's still out there in space.
• 8:36
  Speaker 1: Got it, Okay? And so the listeners were very interested
• 8:40
  Speaker 1: or very aware of the extinction events where an asteroid
• 8:43
  Speaker 1: wiped out the dinosaurs. And then there was another person
• 8:47
  Speaker 1: who wanted to know if when the early Earth got
• 8:50
  Speaker 1: hit and the Moon split off, does maybe that count? Yeah,
• 8:53
  Speaker 1: the listeners are pretty darn well informed.
• 8:56
  Speaker 2: I'd say it's almost like they're listening to an awesome
• 8:59
  Speaker 2: podcast regularly that teaches them all about the Solar System
• 9:02
  Speaker 2: and the universe. Congrats and they pass the exam. But
• 9:08
  Speaker 2: you're right that it is important to understand, like what's
• 9:11
  Speaker 2: out there in the Solar System, where is this stuff
• 9:13
  Speaker 2: coming from? What are the sizes we expect for things
• 9:16
  Speaker 2: that are raining down on the Earth this death from above?
• 9:20
  Speaker 1: Okay, So we've done like an overview of definitions. Let's
• 9:24
  Speaker 1: jump into where asteroids come from and give a little
• 9:27
  Speaker 1: bit more background about where you would find asteroids in particular, and.
• 9:32
  Speaker 2: Go so something that you don't often realize when you
• 9:37
  Speaker 2: look up at the night sky is you mostly see
• 9:40
  Speaker 2: stars and planets, and you think about the Solar System
• 9:43
  Speaker 2: in terms of, you know, like the Sun and the
• 9:45
  Speaker 2: planets and maybe a couple of moons here or there.
• 9:48
  Speaker 2: But the Solar System is much much dirtier than that.
• 9:50
  Speaker 2: You know, there's a whole spectrum of chunks of stuff,
• 9:53
  Speaker 2: from the Sun down to planets, down to moons, down
• 9:56
  Speaker 2: to much smaller rocks. And as the stuff gets smaller,
• 10:00
  Speaker 2: becomes much more numerous. So you've like obviously one Sun,
• 10:03
  Speaker 2: a few planets, dozens of moons, But when you get
• 10:07
  Speaker 2: to smaller chunks of stuff, asteroids and meteoroids and all
• 10:11
  Speaker 2: that stuff, there's zillions and billions and even trillions of
• 10:14
  Speaker 2: these things. But of course they're not luminous, right, They
• 10:17
  Speaker 2: don't glow, and they don't reflect as much light because
• 10:20
  Speaker 2: they're small, so you don't mostly see them in the
• 10:22
  Speaker 2: night sky. They're mostly invisible. So the picture I want
• 10:25
  Speaker 2: to paint in your mind is space being filled basically
• 10:28
  Speaker 2: with dark rocks.
• 10:30
  Speaker 1: Wait, so I have an important question. Yeah, So in
• 10:33
  Speaker 1: Star Wars, this is how all important questions start in
• 10:37
  Speaker 1: Star Wars, when they're like trying to navigate around rocks
• 10:41
  Speaker 1: and space. There's just like they're everywhere and you can't
• 10:44
  Speaker 1: get around them. If you were out in space and
• 10:46
  Speaker 1: you were to stand on like one chunk of something,
• 10:49
  Speaker 1: would you be able to see other chunks of stuff nearby?
• 10:52
  Speaker 1: Or even though there's lots of them, are they still
• 10:54
  Speaker 1: like pretty darn spread out or is it like Star Wars.
• 10:58
  Speaker 2: No, it's a great question. It's not like Star Wars.
• 11:01
  Speaker 2: It turns out Star Wars not a documentary, not a
• 11:04
  Speaker 2: reliable way to plan your space mission.
• 11:09
  Speaker 1: Who you got to know? That would have been embarrassing
• 11:11
  Speaker 1: to say that public.
• 11:13
  Speaker 2: But no, these rocks are pretty big. But they're also
• 11:17
  Speaker 2: very far apart. Because space is vast, especially as you
• 11:20
  Speaker 2: get out into the further reaches of the Solar System,
• 11:23
  Speaker 2: the amount of space between these planets gets enormous, right,
• 11:28
  Speaker 2: The volume of the sphere goes as the radius cube,
• 11:31
  Speaker 2: and so if you're like another million miles away from
• 11:34
  Speaker 2: the Sun, then you create a volume of space which
• 11:37
  Speaker 2: is much much bigger than everything inside of it. And
• 11:40
  Speaker 2: so even though there are lots and lots of asteroids
• 11:43
  Speaker 2: out there, remnants from the formation of the Solar System
• 11:47
  Speaker 2: that didn't pull together into planets or were disturbed by
• 11:51
  Speaker 2: the gravity of Jupiter, for example, to prevent them from coalescing.
• 11:55
  Speaker 2: They're far enough apart that you can't really have that's
• 11:57
  Speaker 2: sort of like exciting space dodgem game.
• 12:00
  Speaker 1: Well, you've dashed a lot of Star Wars related dreams today,
• 12:03
  Speaker 1: but it's important to know, so, all right, So where
• 12:06
  Speaker 1: do you find most.
• 12:07
  Speaker 2: Of these So most of these things are in the
• 12:10
  Speaker 2: asteroid belt, this region between Mars and Jupiter. And that's
• 12:14
  Speaker 2: no accident. You know, as the Solar System is forming,
• 12:17
  Speaker 2: it clumps together, mostly into the Sun and then into
• 12:20
  Speaker 2: the planets, and planets form when you have like a
• 12:23
  Speaker 2: seed of a heavy object, something that can pull stuff
• 12:25
  Speaker 2: together and generate its own gravitational well, rather than just
• 12:28
  Speaker 2: getting sucked into the Sun. But because Jupiter became so big,
• 12:32
  Speaker 2: it's gravity was strong enough that it disrupted the formation
• 12:36
  Speaker 2: of other stuff. And so that's why, for example, these
• 12:39
  Speaker 2: asteroids near Mars Jupiter, even though they've been around for
• 12:42
  Speaker 2: billions of years, they haven't like gradually coalesced into one
• 12:46
  Speaker 2: big object. There's lots and lots of them over there.
• 12:49
  Speaker 1: Oh, it's kind of fun to imagine what it would
• 12:50
  Speaker 1: have been like to have another planet out there. It's
• 12:52
  Speaker 1: like Jupiter.
• 12:54
  Speaker 2: Another way you can see the effect of Jupiter on
• 12:57
  Speaker 2: these asteroids is that there's a bunch of astrailids in
• 13:00
  Speaker 2: orbit with Jupiter. If you draw an ellipse for where
• 13:03
  Speaker 2: Jupiter goes around the Sun, it's not actually totally empty.
• 13:07
  Speaker 2: There's a whole cluster of asteroids that are leading Jupiter
• 13:10
  Speaker 2: and another cluster that are following Jupiter. They're called the
• 13:13
  Speaker 2: Greeks and the Trojans. These two like different camps of asteroids.
• 13:17
  Speaker 1: So I thought that planets were supposed to clear their orbits.
• 13:20
  Speaker 1: Does that okay?
• 13:22
  Speaker 2: All right?
• 13:23
  Speaker 1: But Jupiter is huge, so all right, go on.
• 13:27
  Speaker 2: So if you were like a lawyer for Pluto, you
• 13:29
  Speaker 2: might raise this objection and say, hey, folks, you've been
• 13:31
  Speaker 2: inconsistent here because planets are supposed to clear their orbit.
• 13:35
  Speaker 2: But you know, when planets get big enough, then they
• 13:37
  Speaker 2: can actually collect asteroids in these lagrange points, these points
• 13:41
  Speaker 2: where the Sun and Jupiter's gravity balances out in a
• 13:44
  Speaker 2: way that there's like a little gravitational well there for
• 13:48
  Speaker 2: asteroids to collect in. But it's super cool. We're actually
• 13:51
  Speaker 2: sending a mission to go visit these Trojans pretty soon
• 13:54
  Speaker 2: be a lot of fun.
• 13:55
  Speaker 1: Wait your what.
• 13:56
  Speaker 2: We have a mission that's going to go visit the
• 13:58
  Speaker 2: asteroid belt and one of these trojans.
• 14:00
  Speaker 1: Ooh, that's exciting.
• 14:02
  Speaker 2: Yeah, we had a whole podcast episode about it, Me
• 14:04
  Speaker 2: and you, so check that one out if you're curious
• 14:07
  Speaker 2: about it. But even though you imagine this space to
• 14:10
  Speaker 2: be filled with rocks, and some of these are pretty big,
• 14:12
  Speaker 2: like Series is a whole dwarf planet in this region.
• 14:15
  Speaker 2: It's like nine hundred kilometers in diameter, So that's pretty big.
• 14:19
  Speaker 2: I mean, it's like a tenth or thirteenth of the
• 14:21
  Speaker 2: radius of Earth. That's the biggest thing out there in
• 14:24
  Speaker 2: the asteroid belt. But after that it pretty much falls off.
• 14:28
  Speaker 2: Like half of the mass of the asteroid Belt is
• 14:30
  Speaker 2: in just four big Mama asteroids. After that, it's a
• 14:34
  Speaker 2: bunch of smaller stuff.
• 14:35
  Speaker 1: And those big Mama asteroids are stay input.
• 14:38
  Speaker 2: I hope mostly they stay input. NaSTA does a really
• 14:42
  Speaker 2: good job of tracking these folks and thinking about their trajectory.
• 14:45
  Speaker 2: They can predict them out to about one hundred years
• 14:48
  Speaker 2: from now. After that, it's too chaotic with all the
• 14:50
  Speaker 2: influence from Jupiter and Saturn and the other little bits
• 14:53
  Speaker 2: of the asteroid belt for them to reliably predict where
• 14:56
  Speaker 2: they're going to be. But mostly they know where all
• 14:58
  Speaker 2: the big ones are and they know they're not going
• 15:00
  Speaker 2: to hit us in the next one hundred years.
• 15:02
  Speaker 1: All right, all right, that's that certainty that I can handle.
• 15:05
  Speaker 1: I'll sleep tonight, all right. So, so half of the
• 15:09
  Speaker 1: mass is in those four objects, and how is the
• 15:11
  Speaker 1: rest of the mass distributed?
• 15:13
  Speaker 2: So after that it's lots of tiny little ones. And
• 15:16
  Speaker 2: you know, it used to be much more. It used
• 15:19
  Speaker 2: to be that the asteroid belt had like one hundred
• 15:20
  Speaker 2: or a thousand times as much mass as it does.
• 15:23
  Speaker 2: But when it's so dense over there, they will eventually
• 15:25
  Speaker 2: bump into each other or even just pull on each
• 15:28
  Speaker 2: other gravitationally and fall out of orbit and then plummet
• 15:31
  Speaker 2: into the Sun. So something like ninety nine point ninety
• 15:34
  Speaker 2: percent of the mass of the asteroid belt is gone.
• 15:37
  Speaker 2: It was lost in the first one hundred million years
• 15:40
  Speaker 2: of the Solar System. And what's left is a bunch
• 15:42
  Speaker 2: of smaller asteroids. But even if you add it all
• 15:45
  Speaker 2: up together, it's not even that much stuff. It's like
• 15:48
  Speaker 2: four or five percent the mass of the Moon. If
• 15:51
  Speaker 2: you like gathered it all together into one big ball.
• 15:54
  Speaker 1: So do we need to worry about like so you
• 15:55
  Speaker 1: said most of it has already fallen into the Sun
• 15:58
  Speaker 1: or presumably fallen into Jupiter or something. Is the rest
• 16:01
  Speaker 1: of it? Something like if voyager, you know, was going
• 16:03
  Speaker 1: out past Jupiter, did we have to worry about it
• 16:05
  Speaker 1: running into that stuff? Or there's just not that much
• 16:08
  Speaker 1: of it out there?
• 16:09
  Speaker 2: There's not that much of it out there. Yeah, if
• 16:11
  Speaker 2: you pointed a spaceship through the asteroid belt, you'd have
• 16:13
  Speaker 2: a very small chance of hitting anything.
• 16:15
  Speaker 1: Nice. That's good to hear.
• 16:18
  Speaker 2: Yeah, so you can put your kids on that spaceship
• 16:20
  Speaker 2: and send amount of space without worrying about it.
• 16:22
  Speaker 1: Kelly, No, No, my kids are staying here. I wrote
• 16:29
  Speaker 1: a whole book on why this is a bad idea,
• 16:32
  Speaker 1: four years of my life. My kids are staying here
• 16:35
  Speaker 1: unless they want to go, and then I probably won't stop. Okay,
• 16:39
  Speaker 1: let's take a break. So we've talked about the asteroid
• 16:42
  Speaker 1: belt between Mars and Jupiter. There are other clumps of
• 16:45
  Speaker 1: death from above, and we'll get to that after the break,
• 17:01
  Speaker 1: all right, So, Daniel, where else are these clumps of death?
• 17:06
  Speaker 1: Where else could they be coming from if they're going
• 17:08
  Speaker 1: to be heading towards Earth.
• 17:10
  Speaker 2: So the asteroids are not really something to worry about.
• 17:12
  Speaker 2: We know where most of the big ones are, as
• 17:14
  Speaker 2: we said, and we know where they're going to be.
• 17:16
  Speaker 2: The more dangerous things are further out in the Solar system,
• 17:20
  Speaker 2: out in the Kuiper Belt, like past Neptune, like between
• 17:23
  Speaker 2: thirty and fifty AU, is a bunch of frozen ice cubes,
• 17:27
  Speaker 2: essentially out past the snow line where the Sun is
• 17:31
  Speaker 2: not powerful enough to vaporize. Ice can still be a
• 17:34
  Speaker 2: big factor in the formation of clumps of stuff and
• 17:37
  Speaker 2: also planets. Right, That's why we call Neptune and Urinus
• 17:40
  Speaker 2: the ice giants. So out there in the Kuiper Belt,
• 17:43
  Speaker 2: they're basically a bunch of big frozen snowballs, and sometimes
• 17:47
  Speaker 2: some of them fall towards the center of the Solar system,
• 17:49
  Speaker 2: and those are comets because as they burn their way
• 17:52
  Speaker 2: towards the Sun, the Sun is then boiling stuff off
• 17:55
  Speaker 2: of them, making that tail.
• 17:57
  Speaker 1: And you maybe already said this, and I guess I
• 17:58
  Speaker 1: just didn't understand. What, why are we more at risk
• 18:01
  Speaker 1: from stuff in the Kuiper Belt than the asteroid belt,
• 18:03
  Speaker 1: which is closer is there movement just more chaotic.
• 18:07
  Speaker 2: Well, for two reasons. One is they come from further out,
• 18:10
  Speaker 2: so that by the time they make it into our
• 18:11
  Speaker 2: inner neighborhood of the Solar System, they're moving faster, like
• 18:15
  Speaker 2: they've fallen further into a gravity well. And velocity is
• 18:18
  Speaker 2: important because the faster you're moving when you hit the Earth,
• 18:21
  Speaker 2: the more energy you're depositing, the more the seismic waves,
• 18:24
  Speaker 2: the more stuff you toss up into the atmosphere. Velocity
• 18:27
  Speaker 2: does matter. The other reason is that these things are
• 18:30
  Speaker 2: harder to study. They're further away, so they're harder to spot,
• 18:34
  Speaker 2: and they're more erratic. They're more susceptible to like passing
• 18:38
  Speaker 2: stars that give them a little gentle tug and nudge
• 18:41
  Speaker 2: them in towards the center of the Solar System. And
• 18:43
  Speaker 2: there's so many of them out there that we can't
• 18:45
  Speaker 2: possibly track all of them, so they're harder to spot
• 18:48
  Speaker 2: and higher speeds.
• 18:50
  Speaker 1: I don't like it all.
• 18:52
  Speaker 2: Right, Well, then you're definitely not going to like. The
• 18:54
  Speaker 2: Org cloud, even further away from the Sun is a
• 18:57
  Speaker 2: theoretical cloud of basically icy many planets. We think there
• 19:01
  Speaker 2: might be trillions of objects in there that are more
• 19:05
  Speaker 2: than a kilometer wide, and maybe even billions that are
• 19:08
  Speaker 2: twenty kilometers wide. You said theoretical, Yes, theoretical.
• 19:12
  Speaker 1: I had assumed we knew this about the Ork Cloud already.
• 19:15
  Speaker 1: This is just like stuff we think. I mean, I
• 19:17
  Speaker 1: guess it makes sense. It's really far away, but we're
• 19:19
  Speaker 1: we just think it's out there. We're not sure.
• 19:21
  Speaker 2: We think the Orc Cloud is out there. It makes sense,
• 19:23
  Speaker 2: it's part of all of our simulations. It's been predicted,
• 19:26
  Speaker 2: but we've never actually seen something in the Ork Cloud
• 19:29
  Speaker 2: because it is super duper far away. These things are
• 19:33
  Speaker 2: like one to three light ears from the Sun.
• 19:37
  Speaker 1: But it's on a bunch of the illustrations I've seen.
• 19:41
  Speaker 2: Artists' conceptions. Oh my gosh, I know. No, this is
• 19:45
  Speaker 2: basically an interstellar space. It's not really part of the
• 19:48
  Speaker 2: heliosphere or the Solar system. But we do think it's
• 19:51
  Speaker 2: part of the gravitational system of the Sun, and there's
• 19:54
  Speaker 2: a lot of stuff out there. Theoretically, it's much further
• 19:56
  Speaker 2: out than like even where Voyager one has gone, and
• 20:00
  Speaker 2: it's so far away, and these things are pretty small,
• 20:02
  Speaker 2: so it's hard to spot them directly.
• 20:04
  Speaker 1: Well, Voyager one gets there before it runs out of power.
• 20:08
  Speaker 2: It's going to take like three hundred years for Voyager
• 20:10
  Speaker 2: one to get there, and it basically ran out of power. Recently,
• 20:13
  Speaker 2: I heard that they stopped hearing from it, so we
• 20:16
  Speaker 2: already know the end of that story.
• 20:18
  Speaker 1: Oh oh, that's really sad. I can't believe I missed that. Yes,
• 20:22
  Speaker 1: Christ in Peace one.
• 20:23
  Speaker 2: Exactly, or floating piece or whatever you say out there
• 20:27
  Speaker 2: in space. The Ork Cloud is theoretical. We're fairly confident
• 20:31
  Speaker 2: it's there. We see indirections, and also we think it's
• 20:34
  Speaker 2: the source of the longer period comets. Because these things
• 20:37
  Speaker 2: are so far away, they take a long time to
• 20:39
  Speaker 2: make it into the Inner Solar System and maybe impact
• 20:43
  Speaker 2: on a juicy Inner Solar System planet or not. And
• 20:47
  Speaker 2: so the shorter period comets probably come from the Kuiper Belt,
• 20:50
  Speaker 2: and the longer period comets with even more mass and
• 20:53
  Speaker 2: even more velocity come from the Org Cloud.
• 20:56
  Speaker 1: Have we seen something come closer to us that we
• 20:59
  Speaker 1: think came from ort cloud.
• 21:00
  Speaker 2: Well, we've definitely seen a lot of long period comets,
• 21:03
  Speaker 2: these comments that take centuries sometimes to orbit the Solar System,
• 21:07
  Speaker 2: and so we think that they originated from the Ork Cloud.
• 21:10
  Speaker 2: So yeah, we think those things are visitors from the
• 21:12
  Speaker 2: Ork Cloud. And that's one reason why people are excited
• 21:15
  Speaker 2: to like go sample comets while they're sending probes out
• 21:18
  Speaker 2: there to grab bits of comments to see, like what
• 21:21
  Speaker 2: is it like out there in the Orc cloud. Be
• 21:23
  Speaker 2: awesome to get a sample of the Ork cloud that
• 21:26
  Speaker 2: visited the Inner Solar System.
• 21:27
  Speaker 1: Okay, so we've talked about where these things reside. Let's
• 21:33
  Speaker 1: talk a little bit more about size. So like, if
• 21:36
  Speaker 1: something that's a meter in diameter comes at us, that's
• 21:42
  Speaker 1: not a problem, right, that's going to burn up.
• 21:44
  Speaker 2: That's not a problem. That's actually kind of awesome. Yeah,
• 21:46
  Speaker 2: it makes really nice streak in the sky. It doesn't
• 21:49
  Speaker 2: really do any damage. And also it happens all the time.
• 21:52
  Speaker 2: You know, space, as we said, is filled with dark rocks.
• 21:54
  Speaker 2: Is not just the asteroids that we've cataloged in the
• 21:57
  Speaker 2: asteroid belt. There's rocks out there all over the place,
• 22:00
  Speaker 2: just floating free, tugged by Jupiter here and there. And
• 22:03
  Speaker 2: that's why we see meteor showers. Right, Every meteor shower
• 22:06
  Speaker 2: are a bunch of rocks hitting the Earth. Fortunately, our
• 22:09
  Speaker 2: atmosphere is dense enough to act like a big pillow,
• 22:13
  Speaker 2: and so when they hit the atmosphere, there's friction, they
• 22:16
  Speaker 2: heat up and then they burn up before they hit
• 22:18
  Speaker 2: the ground. And so stuff that's less than a meter
• 22:21
  Speaker 2: in size, it happens all the time.
• 22:23
  Speaker 1: Yeah, a big slammable pillow.
• 22:24
  Speaker 2: You know.
• 22:25
  Speaker 1: I was when I was researching the spacebook, and we
• 22:29
  Speaker 1: were looking at companies that had sort of like out
• 22:32
  Speaker 1: there ways of planning to make money on space stuff.
• 22:35
  Speaker 1: There was a company that was pitching that they could
• 22:39
  Speaker 1: make you essentially like asteroid meteor shower sorts of things
• 22:44
  Speaker 1: by like sending masks to space and then having it
• 22:47
  Speaker 1: come down at a certain time, and that they could
• 22:49
  Speaker 1: like determine the colors that it would be. Wow, so like,
• 22:52
  Speaker 1: you know, the most epic birthday present, like a pink
• 22:56
  Speaker 1: meteor shower for your Kinsania.
• 22:59
  Speaker 2: But anyway, that sounds like there's no way that could
• 23:02
  Speaker 2: go wrong. Yeah, absolutely, that doesn't sound dangerous at all.
• 23:07
  Speaker 1: No, No, it's great, it's great. Okay, all right, so
• 23:12
  Speaker 1: we've got a meter and it's beautiful. When does it
• 23:15
  Speaker 1: start becoming less beautiful and more scary?
• 23:18
  Speaker 2: Yeah, So there's this trade off. As they get larger,
• 23:21
  Speaker 2: they get more dangerous, and fortunately they also get less common. So,
• 23:26
  Speaker 2: for example, stuff that's like a meter wide hits the
• 23:29
  Speaker 2: Earth around once per day, and that's not that big
• 23:32
  Speaker 2: a deal. I mean, you can make a big explosion
• 23:34
  Speaker 2: in the sky and it's the kind of stuff that
• 23:36
  Speaker 2: you hear about, you know, like the churbulence explosion in
• 23:39
  Speaker 2: Russia recently. It's an order magnitude of a meter size thing.
• 23:44
  Speaker 2: Often this just happens, you know, over the ocean. Nobody notices,
• 23:47
  Speaker 2: but occasionally you get a bigger one. And if you
• 23:50
  Speaker 2: had something like ten or twenty meters wide, this happens
• 23:53
  Speaker 2: like every ten or fifty years, then you're starting to
• 23:57
  Speaker 2: get energies comparable to an atomic bomb explosion.
• 24:00
  Speaker 1: WHOA, I feel like we should hear about that more often.
• 24:03
  Speaker 1: But I guess I guess you said that it happens
• 24:05
  Speaker 1: over the ocean a lot, and so we wouldn't hear
• 24:06
  Speaker 1: about it.
• 24:07
  Speaker 2: Yeah. I had exactly the same reaction. I was like,
• 24:09
  Speaker 2: hold on, a second, nuclear bomb explosions not that common.
• 24:13
  Speaker 2: You think you'd hear about it. This is beyond the news.
• 24:16
  Speaker 2: You'd feel it or something. But these things tend to
• 24:18
  Speaker 2: happen in the upper atmosphere and often over the ocean,
• 24:21
  Speaker 2: so they're just not observed or reported.
• 24:23
  Speaker 1: But with how much like surveillance equipment we have in space,
• 24:27
  Speaker 1: I would expect you'd see it. But I guess that
• 24:29
  Speaker 1: surveillance equipment, you know, has only been up there since
• 24:32
  Speaker 1: like the sixties or something like that, so we don't
• 24:34
  Speaker 1: have that many years of data. Wow, Okay, that's the
• 24:39
  Speaker 1: numbers you're giving are much more regular than I would
• 24:42
  Speaker 1: have guessed. Let's move on.
• 24:44
  Speaker 2: Yeah, and it's also energy deposited in the upper atmosphere,
• 24:47
  Speaker 2: so it's not like the equivalent of somebody sitting off
• 24:49
  Speaker 2: a nuclear weapon on land or even dropping one in
• 24:52
  Speaker 2: the ocean. And so while the military is definitely tracking
• 24:55
  Speaker 2: these things, and we talked about like the network of
• 24:58
  Speaker 2: satellites that the military has when we're talking recently about
• 25:01
  Speaker 2: interstellar asteroids and whether they've hit the Earth and whether
• 25:03
  Speaker 2: Avilobe has actually gathered any spherials from them. So we
• 25:07
  Speaker 2: know the folks are tracking them, it's just not that
• 25:09
  Speaker 2: big a deal. It's like getting your shields zapped with lasers,
• 25:12
  Speaker 2: but you know your shields are pretty strong.
• 25:14
  Speaker 1: Okay, all right, So these explosions are happening in the atmosphere.
• 25:17
  Speaker 1: So have we talked about a size yet that could
• 25:21
  Speaker 1: reach the Earth, and is there a relationship between size
• 25:25
  Speaker 1: and whether Yeah, there's got to be a relationship between
• 25:27
  Speaker 1: size and whether or not it makes it to the
• 25:29
  Speaker 1: Earth to impact, right.
• 25:30
  Speaker 2: Yeah, So anything above like twenty five or fifty meters
• 25:35
  Speaker 2: will probably make it to the surface. Anything smaller than
• 25:38
  Speaker 2: that is probably going to burn up in the atmosphere.
• 25:41
  Speaker 2: And once you get up to that size, we're talking
• 25:42
  Speaker 2: about a significant amount of energy. So like one hundred
• 25:46
  Speaker 2: meters size asteroid if it hits, which is something that
• 25:49
  Speaker 2: happens every few thousand years, we think has as much
• 25:52
  Speaker 2: energy as three thousand atomic bombs.
• 25:55
  Speaker 1: Oh my gosh, Okay, so five thousand years. How long
• 25:57
  Speaker 1: have we had recorded history? Do we have? And I
• 26:01
  Speaker 1: know it could have happened in the ocean and we
• 26:04
  Speaker 1: missed it or something, But do we have any recorded
• 26:07
  Speaker 1: histories of this sort of thing happening?
• 26:09
  Speaker 2: We do, we think, and we're going to dig into
• 26:11
  Speaker 2: that in just a minute.
• 26:12
  Speaker 1: Who suspenseful?
• 26:15
  Speaker 2: And then as the things get larger, like a kilometer wide,
• 26:18
  Speaker 2: we're talking about something every half million years. We think
• 26:22
  Speaker 2: probably five kilometer wide asteroids happen every twenty to forty
• 26:26
  Speaker 2: million years, and basically anything above five or ten kilometers
• 26:31
  Speaker 2: is extinction level event. We're talking about creating creators that
• 26:34
  Speaker 2: are like one hundred kilometers wide, tossing up enormous amounts
• 26:38
  Speaker 2: of stuff into the atmosphere, obliterating a consonant instantly with fireballs,
• 26:43
  Speaker 2: so like an enormous amount of energy, but fortunately very
• 26:46
  Speaker 2: very rare.
• 26:47
  Speaker 1: I don't know what to say other than maybe I'm
• 26:49
  Speaker 1: not going to be sleeping tonight. Maybe I take it back.
• 26:53
  Speaker 2: And so, of course we're really curious about if this
• 26:55
  Speaker 2: is going to happen in the future, and when we
• 26:57
  Speaker 2: can also look around the Earth for signs at this
• 27:00
  Speaker 2: this happened because it's hit the Moon, it's hit basically
• 27:03
  Speaker 2: every surface in the Solar System. The Earth is not special.
• 27:06
  Speaker 2: The Earth also gets hit with this stuff, but only
• 27:09
  Speaker 2: the larger ones make it down to the surface and
• 27:12
  Speaker 2: cause impact craters.
• 27:13
  Speaker 1: So now I'm realizing that I would love to know
• 27:16
  Speaker 1: how we figured out these frequency data that you said.
• 27:19
  Speaker 1: You know, how do we know that you get a
• 27:21
  Speaker 1: five meter size one almost every five years? And how
• 27:25
  Speaker 1: can we search the Earth for evidence of how often
• 27:29
  Speaker 1: it got hit? Are you saying that we don't bother
• 27:31
  Speaker 1: searching the Earth because it's easier to just look at
• 27:34
  Speaker 1: the Moon.
• 27:34
  Speaker 2: These are extrapolations from our stimulations of like what's out
• 27:37
  Speaker 2: there in the Solar system, how often do we expect
• 27:40
  Speaker 2: stuff to hit the Earth. We can also verify those
• 27:43
  Speaker 2: and a lot of those stimulations are built on studies
• 27:46
  Speaker 2: of impact craters on the Moon and other objects, the
• 27:48
  Speaker 2: Moon just being super close by and like riddled with
• 27:51
  Speaker 2: impact craters, and they do all sorts of cool studies
• 27:54
  Speaker 2: to see like the age of craters on the Moon,
• 27:56
  Speaker 2: by seeing how they're layered, Like if you have a
• 27:59
  Speaker 2: fresh then it's gonna have no other craters inside of it,
• 28:02
  Speaker 2: whereas an old crater is gonna have lots of other
• 28:05
  Speaker 2: small craters within it. And so you can tell the
• 28:08
  Speaker 2: age of these craters on the Moon by like how
• 28:10
  Speaker 2: many other craters have been layered on top of them.
• 28:12
  Speaker 2: It's super cool.
• 28:13
  Speaker 1: That is super cool. And if we couldn't do that
• 28:16
  Speaker 1: on Earth because that stuff gets covered up too fast,
• 28:18
  Speaker 1: is that right?
• 28:19
  Speaker 2: No, we do actually have evidence of craters here on Earth,
• 28:22
  Speaker 2: though it is more complicated because we have weather and
• 28:25
  Speaker 2: we have an atmosphere, and so only the bigger stuff
• 28:27
  Speaker 2: leaves evidence. But there's lots of cool ways that people
• 28:30
  Speaker 2: have figured out that formations on Earth are due to impact,
• 28:35
  Speaker 2: Like there's certain kinds of rock that are only formed
• 28:38
  Speaker 2: when you get a super high energy impact, Like shocked quartz.
• 28:43
  Speaker 2: This is a structure of quartz that's only formed under
• 28:46
  Speaker 2: extremely high pressure. Like you squeeze quartz hard enough and
• 28:50
  Speaker 2: it changes its crystal structure and it stays that way
• 28:54
  Speaker 2: even after you remove the pressure.
• 28:56
  Speaker 1: I like that name shocked quartz. It was like, Oh,
• 28:59
  Speaker 1: that's a surprising explosion.
• 29:02
  Speaker 2: It sucks. We only actually discovered it recently in nuclear
• 29:06
  Speaker 2: testing craters, Like when we started creating these conditions, these
• 29:10
  Speaker 2: nuclear bombs, we discovered this shock courts. Then we found
• 29:13
  Speaker 2: it in other places on Earth. We're like, oh, wow,
• 29:16
  Speaker 2: this must have been a big explosion too, thousands of
• 29:19
  Speaker 2: years ago. So it's kind of cool how modern technology
• 29:23
  Speaker 2: has enabled us to discover the secrets of the past.
• 29:26
  Speaker 1: So many positives to nuclear bomb testing.
• 29:32
  Speaker 2: But earlier you were asking whether we have evidence for
• 29:35
  Speaker 2: like these sort of smaller collisions in the recent past,
• 29:38
  Speaker 2: And maybe my favorite one is in Estonia. This evidence
• 29:42
  Speaker 2: in Estonia of an impact that left a crater that's
• 29:44
  Speaker 2: like one hundred meters wide, and they think it happened
• 29:47
  Speaker 2: in fifteen hundred BC, So this is just a few
• 29:51
  Speaker 2: thousand years ago, you know, as we were saying, like,
• 29:53
  Speaker 2: we expect one hundred meter wide impactors every few thousand years.
• 29:58
  Speaker 2: So do we have any written history of this? And
• 30:00
  Speaker 2: this is a great candidate.
• 30:01
  Speaker 1: Go on, So is it the ancient Egyptians? They did
• 30:05
  Speaker 1: a lot of writing.
• 30:07
  Speaker 2: The ancient Egyptians did a lot of writing. But these
• 30:10
  Speaker 2: are lakes in Estonia that they're pretty certain were caused
• 30:13
  Speaker 2: by an impact. They're like these big circular lakes, and
• 30:16
  Speaker 2: they suspect that they may actually appear in Estonian and
• 30:19
  Speaker 2: Finnish mythology. So now this is very tenuous, of course,
• 30:23
  Speaker 2: but you know, you're wondering, like ancient peoples when they
• 30:25
  Speaker 2: saw this thing, what did they think? How they describe it?
• 30:28
  Speaker 2: How would it appear in their records? Because they're not
• 30:31
  Speaker 2: all doing astronomy. I mean, the ancient Chinese have like
• 30:34
  Speaker 2: astronomical records way way back then, but we don't have
• 30:37
  Speaker 2: astronomical records from everybody. You, of course, are familiar with
• 30:40
  Speaker 2: the famous work of literature of Beowulf.
• 30:43
  Speaker 1: I am indeed yeh, because you're the best adaptation ever
• 30:47
  Speaker 1: has been written by my husband for children, because who
• 30:50
  Speaker 1: didn't want the Beowolf for children version?
• 30:53
  Speaker 2: Yes, well exactly, And so spoiler alert, Beowulf dies in
• 30:57
  Speaker 2: the end, and he dies the hands of a fiery dragon.
• 31:01
  Speaker 2: And in the text they call it the sky Plague,
• 31:03
  Speaker 2: a long creature that flew at night over the coast
• 31:06
  Speaker 2: of Greystone Cliffs, and in the poem it uses its fiery,
• 31:10
  Speaker 2: poisonous breath to scorch and depopulate the countryside. And some
• 31:14
  Speaker 2: people think I read a sociology paper that says that
• 31:17
  Speaker 2: the description of the dragon and the devastation it causes
• 31:20
  Speaker 2: has a lot in common with this impact site in Collie,
• 31:24
  Speaker 2: And there are indeed Greystone Cliffs dearby, and so it
• 31:28
  Speaker 2: could be that, like some fiery impact left its traces
• 31:32
  Speaker 2: in the local mythology and ended up in the text
• 31:34
  Speaker 2: of Beowulf.
• 31:35
  Speaker 1: WHOA, that's pretty cool.
• 31:38
  Speaker 2: And you know this is not scientific, of course, it's
• 31:40
  Speaker 2: always very easy to come up with a connection where
• 31:43
  Speaker 2: there isn't one. But it's fun to imagine how these
• 31:46
  Speaker 2: people might have thought about these huge, devastating impact And
• 31:49
  Speaker 2: it's something you can go and visit today. It's called Kali.
• 31:52
  Speaker 2: I'm sure, I'm pronouncing it incorrectly kaa l I. And
• 31:56
  Speaker 2: it's a site in Estonia with obvious impact craters.
• 32:00
  Speaker 1: It's a wonderful work of fiction, particularly if you're reading
• 32:04
  Speaker 1: the version written by my husband called be Wolf.
• 32:07
  Speaker 2: Exactly, and it may have inspired some of the great
• 32:09
  Speaker 2: literature of our civilization. But you don't actually have to
• 32:13
  Speaker 2: travel to Estonia to see impact creators. We have an
• 32:15
  Speaker 2: awesome one right here in.
• 32:17
  Speaker 1: The US, and after a break, we'll tell you where
• 32:20
  Speaker 1: you can find it. All right, So, for your listeners
• 32:35
  Speaker 1: who reside in the United States, if we want to
• 32:37
  Speaker 1: visit our nation's crater, where would we go?
• 32:42
  Speaker 2: So in Arizona, there's a place well named. It's called
• 32:46
  Speaker 2: Meteor Crater, and it's the side of an impact from
• 32:49
  Speaker 2: forty seven thousand BC, so this is like almost fifty
• 32:53
  Speaker 2: thousand years ago. But it's not a small site. This
• 32:56
  Speaker 2: crater is more than a kilometer across, and it's just
• 33:00
  Speaker 2: it's like out there in the desert. It's just like
• 33:02
  Speaker 2: huge vast plains and then all of a sudden, enormous
• 33:04
  Speaker 2: impact crater. You can see this thing one flying over Arizona.
• 33:08
  Speaker 2: It's like very obvious.
• 33:10
  Speaker 1: This one. I happened to know is nickel iron if
• 33:13
  Speaker 1: it had been ice but it was the same size
• 33:17
  Speaker 1: and going the same speed, would it matter or is
• 33:20
  Speaker 1: it about size and speed and mass?
• 33:22
  Speaker 2: Yeah, great question, It wouldn't matter so much. Like you
• 33:25
  Speaker 2: get a similar impact crater, but this one actually left
• 33:27
  Speaker 2: a meteor right because it's made of nickel an iron.
• 33:30
  Speaker 2: A lot of it survived, like half of it was
• 33:33
  Speaker 2: vaporized when it came through the atmosphere and smashed into
• 33:36
  Speaker 2: the earth, but huge chunks of it are still lying around.
• 33:40
  Speaker 2: They have found chunks of this asteroid before it came
• 33:42
  Speaker 2: a meteor and now the chunks of it are called meteorite,
• 33:45
  Speaker 2: so we can actually study it.
• 33:47
  Speaker 1: Whoa dude like, is this something you can buy online?
• 33:49
  Speaker 1: Is there that much of it?
• 33:51
  Speaker 2: There's not that much of it. It's very scientifically valuable.
• 33:55
  Speaker 2: But it also played an important role in understanding how
• 33:58
  Speaker 2: to date geological events. Like one way we figure out
• 34:01
  Speaker 2: how old things are, how old a rock is when
• 34:04
  Speaker 2: it went from lava to some sort of like crystal,
• 34:08
  Speaker 2: is by looking at the uranium inside of it. We
• 34:11
  Speaker 2: can use uranium dating to figure out when a rock
• 34:14
  Speaker 2: was made.
• 34:15
  Speaker 1: And did this have uranium in it or does stuff
• 34:18
  Speaker 1: in space have different amounts of uranium.
• 34:20
  Speaker 2: This stuff has uranium and it so we can use
• 34:22
  Speaker 2: this technique to figure out like when the original chunk
• 34:25
  Speaker 2: of stuff was made before it hit the earth. But
• 34:28
  Speaker 2: it actually also has a really cool story connected to
• 34:30
  Speaker 2: gasoline because when they were trying to figure this stuff out,
• 34:34
  Speaker 2: they need to understand where all the lead was in
• 34:36
  Speaker 2: the atmosphere. The way this dating system works is that
• 34:40
  Speaker 2: when these little crystals form inside the rock, these Zerokon crystals,
• 34:44
  Speaker 2: they allow uranium in, but they strongly reject lead. Like
• 34:47
  Speaker 2: the chemistry of it says lead is not allowed inside
• 34:50
  Speaker 2: these crystals, but uranium decays into lead, and so after
• 34:55
  Speaker 2: millions or billions of years, the uranium has transformed itself
• 34:58
  Speaker 2: into lead. So the more the lead you find inside
• 35:01
  Speaker 2: these crystals, the older the rock is. It's like a
• 35:03
  Speaker 2: little clock turning uranium into lead. And you know there's
• 35:07
  Speaker 2: no lead to start with because the crystal's repel it.
• 35:10
  Speaker 2: So if you can measure the amounts of lead and
• 35:11
  Speaker 2: then mounted uranium, then you can tell how old stuff is.
• 35:14
  Speaker 2: So the chemist who was figuring this stuff out, he
• 35:17
  Speaker 2: was trying to calibrate this and he was discovering, Oh
• 35:19
  Speaker 2: my gosh, this lead everywhere. Like every time he tried
• 35:22
  Speaker 2: to get a lead free environment just to like calibrate
• 35:25
  Speaker 2: his measurements and do some tests, he was totally unable to.
• 35:28
  Speaker 2: He had to actually go to Arizona and study a
• 35:31
  Speaker 2: piece of this meteorite to try to get like an
• 35:33
  Speaker 2: unspoiled piece of rock that didn't have like lead everywhere
• 35:37
  Speaker 2: in it. And that, of course was because we had
• 35:39
  Speaker 2: lead in our gasoline and we were pumping a huge
• 35:41
  Speaker 2: amount of lead into our atmosphere and into our children's mouths.
• 35:46
  Speaker 2: There's lead everywhere in the seventies, and he actually led
• 35:48
  Speaker 2: the charge to get lead out of gasoline, not just
• 35:51
  Speaker 2: because it was making everybody dumber, but also because he
• 35:54
  Speaker 2: didn't like having a lead polluted atmosphere. It made it
• 35:56
  Speaker 2: harder for him to make these measurements. And he's one
• 35:59
  Speaker 2: of the first people to measure the age of the.
• 36:01
  Speaker 1: Earth accurately better living through science.
• 36:03
  Speaker 2: Yeah, and this meteorite helps us all have a safer
• 36:06
  Speaker 2: environment for our children and understand uranium dating.
• 36:09
  Speaker 1: Wow. Well, okay, so that's that's a positive thing for once.
• 36:14
  Speaker 1: Maybe my children can listen to that chunk. But I'll
• 36:17
  Speaker 1: just take out the lead is everywhere a part.
• 36:19
  Speaker 2: Well, lead is no longer everywhere, thankfully.
• 36:22
  Speaker 1: All right, So let's go even further back in time.
• 36:25
  Speaker 1: Presumably we'll talk about an even big asteroid. Where are
• 36:29
  Speaker 1: we going to find this one?
• 36:30
  Speaker 2: So for the next biggest one, we got to go
• 36:32
  Speaker 2: to Kazakhstan. There's a site in zamashin Kazakhstan where an
• 36:37
  Speaker 2: impact left a crater fourteen kilometers wide about a million
• 36:43
  Speaker 2: years ago.
• 36:44
  Speaker 1: Oh okay, so how many hiroshimas would that produce? That's
• 36:48
  Speaker 1: gotta be a lot.
• 36:50
  Speaker 2: That was a really big impact. Absolutely. They think that
• 36:53
  Speaker 2: this is essentially the most recent impact that would have
• 36:57
  Speaker 2: produced a huge nuclear winter. Not large enough to cause
• 37:01
  Speaker 2: a mass extinction, but large enough to really have a
• 37:04
  Speaker 2: serious impact on the Earth's climate for many years. So
• 37:08
  Speaker 2: this was a really large event. I mean, fourteen kilometer
• 37:11
  Speaker 2: wide crater is like nothing to joke about.
• 37:13
  Speaker 1: I'm a little surprised you can have a nuclear winter
• 37:16
  Speaker 1: without a mass extinction, but uh, I guess nature's kind
• 37:20
  Speaker 1: of resilience.
• 37:22
  Speaker 2: By then, the mammals were already in charge, and we'd
• 37:24
  Speaker 2: already survived from one big nuclear winter. So you know,
• 37:26
  Speaker 2: grow out that fur coat and hunker down for a
• 37:29
  Speaker 2: few years we.
• 37:31
  Speaker 1: Got this figured out. Now can I buy any of
• 37:34
  Speaker 1: this online?
• 37:36
  Speaker 2: Actually you can. This one is so big that it
• 37:39
  Speaker 2: left fragments everywhere, and people just go like and pick
• 37:42
  Speaker 2: up the stuff and sell it online. And some of
• 37:44
  Speaker 2: it is really spectacular, Like you can buy this stuff
• 37:47
  Speaker 2: called glass foam, which shows you that the original impactor
• 37:52
  Speaker 2: was kind of fluffy. It had these like big chunks
• 37:55
  Speaker 2: of silicon with huge air bubbles in it. We still
• 37:57
  Speaker 2: don't really understand exactly how it was full. And in
• 38:01
  Speaker 2: some of these chunks of glass foam you can see
• 38:03
  Speaker 2: the melt, like there's unspoiled chunks of glass foam. Then
• 38:06
  Speaker 2: the other side of the rock is like melted glass
• 38:09
  Speaker 2: foam as it passed through the atmosphere and the plasma
• 38:12
  Speaker 2: from the friction actually melted the edge of this thing.
• 38:15
  Speaker 2: It's really pretty spectacular. So yeah, you can just go
• 38:18
  Speaker 2: online and buy Zamanschite.
• 38:20
  Speaker 1: Quite the conversation piece, And you know, there's a lot
• 38:24
  Speaker 1: of studio science surrounding this stuff.
• 38:25
  Speaker 2: People think it's mystical. I look for some of this
• 38:27
  Speaker 2: stuff for sale, and it was advertised as having the
• 38:30
  Speaker 2: capacity to quote blast away bad forces and negative people
• 38:34
  Speaker 2: who block your life's path. So I'm not sure that
• 38:37
  Speaker 2: sounds great big if true, right right, Yeah, so we'll see.
• 38:48
  Speaker 2: I'm not going to endorse those claims, but it is
• 38:50
  Speaker 2: pretty cool to own a chunk of stuff that came
• 38:53
  Speaker 2: from space that like floated around the Solar System for
• 38:56
  Speaker 2: a while and then decided to end its days here
• 38:59
  Speaker 2: on Earth.
• 39:00
  Speaker 1: That is pretty cool, all right. And so now we're
• 39:02
  Speaker 1: going to another stan. We're heading to Jikastan. Tell us
• 39:08
  Speaker 1: about this one.
• 39:09
  Speaker 2: Yeah, So Karakul to Jikastan is the site of a
• 39:12
  Speaker 2: disputed impact. It's basically a huge leak. And when people
• 39:17
  Speaker 2: first went to space and saw pictures of him from space,
• 39:19
  Speaker 2: they were like, hold on a second, look at the
• 39:21
  Speaker 2: shape of that thing. That looks like an impact crater.
• 39:24
  Speaker 1: And that's because it's very circular.
• 39:26
  Speaker 2: It's mostly circular. It's actually got like a big peninsula
• 39:29
  Speaker 2: in the middle. Some people think is also part of
• 39:31
  Speaker 2: the evidence, because when a rock hits the Earth, it
• 39:34
  Speaker 2: can have all sorts of weird seismic bounce backs, So
• 39:37
  Speaker 2: some people think it's consistent with a crater. Some people
• 39:41
  Speaker 2: are like, nah, you're just imagining it. It's like staring
• 39:43
  Speaker 2: at clouds. But If it is an impact crater, it's
• 39:47
  Speaker 2: an enormous one. This thing is fifty kilometers wide, and
• 39:52
  Speaker 2: they think it probably happened somewhere between five and twenty
• 39:55
  Speaker 2: million years ago. So this would have been big news
• 39:59
  Speaker 2: a long time ago.
• 40:00
  Speaker 1: So why do we have to dispute this? Why can't
• 40:02
  Speaker 1: we know for sure? Why can't we look for like
• 40:04
  Speaker 1: shocked quartz or tech tight or something.
• 40:06
  Speaker 2: Yeah, people have done that, but you know, these things
• 40:08
  Speaker 2: aren't easy to find when it's so old. Even the
• 40:10
  Speaker 2: big crater like the one we'll talk about next that
• 40:12
  Speaker 2: killed the dinosaur, it took a long time before people
• 40:14
  Speaker 2: were able to like find the evidence for it. So
• 40:17
  Speaker 2: this one was discovered fairly recently, and people are still
• 40:19
  Speaker 2: studying and still trying to find those pieces of evidence
• 40:22
  Speaker 2: that might be out there.
• 40:23
  Speaker 1: All right, all right, so then let's move on to
• 40:24
  Speaker 1: the dinosaur killer.
• 40:27
  Speaker 2: So probably the most famous impact site on Earth is
• 40:30
  Speaker 2: Do you know how to pronounce this one? Kelly? No,
• 40:33
  Speaker 2: do you want to try on air?
• 40:36
  Speaker 4: Uh?
• 40:37
  Speaker 1: Chick kloop?
• 40:38
  Speaker 2: All right, We're gonna go with that.
• 40:39
  Speaker 1: I think I had a Russian in there. I'm not
• 40:42
  Speaker 1: sure that belongs.
• 40:43
  Speaker 2: Sorry, this is the one in the Yucatan. You know
• 40:45
  Speaker 2: how Mexico basically has that little swoop in it, and
• 40:49
  Speaker 2: they think that that's the edge of an impact crater,
• 40:51
  Speaker 2: the one that probably took out the dinosaurs sixty five
• 40:55
  Speaker 2: million years ago. And this one's enormous, right, it's one
• 40:58
  Speaker 2: hundred and fifty kilometers wide, and they think that an
• 41:02
  Speaker 2: impactor like ten kilometers wide hit the Earth and left
• 41:06
  Speaker 2: that impact crater. One we can see now from space.
• 41:09
  Speaker 2: It's pretty amazing.
• 41:10
  Speaker 1: But we do have shocked quarts and tech tights from
• 41:12
  Speaker 1: this one.
• 41:13
  Speaker 2: From this one, we actually do have very specific evidence.
• 41:15
  Speaker 2: You can see in the ring around the edge, shock
• 41:18
  Speaker 2: quarts everywhere, and they have tech tights, which are these
• 41:20
  Speaker 2: little bits of glass that are created during the impact
• 41:23
  Speaker 2: and then thrown everywhere that are different from volcanic glass
• 41:27
  Speaker 2: and also like don't have the geology of the local environment,
• 41:30
  Speaker 2: so they seem very obviously like created from some impactor.
• 41:34
  Speaker 2: So here we have very strong evidence that there really
• 41:37
  Speaker 2: was an impact sixty five million years ago. People still
• 41:40
  Speaker 2: argue about whether it's the reason the dinosaurs went extinct,
• 41:44
  Speaker 2: et cetera, et cetera, et cetera, but we're pretty confident
• 41:46
  Speaker 2: that it happened, and it would lead to crazy things
• 41:49
  Speaker 2: like tsunamis a kilometer high clouds of dust and ash
• 41:54
  Speaker 2: and steam, including like twenty five trillion tons of material,
• 41:59
  Speaker 2: some of which escaped the Earth and is still floating
• 42:02
  Speaker 2: around in the Solar system, like explosive dust from this
• 42:06
  Speaker 2: impact is still out there.
• 42:08
  Speaker 1: It's crazy, right, that's intense.
• 42:10
  Speaker 2: Yeah, So this is the most famous impact crater on
• 42:13
  Speaker 2: Earth when people know about the most, but it's actually
• 42:15
  Speaker 2: probably not the biggest, the most dramatic impact in Earth's history.
• 42:19
  Speaker 1: No, this is the biggest one that I know about,
• 42:22
  Speaker 1: and I feel pretty good because I think for the listeners,
• 42:26
  Speaker 1: this was the one that most of them talked about
• 42:27
  Speaker 1: as well. So which one is bigger?
• 42:31
  Speaker 2: So there's an impact crater in South Africa. It's called Redifort.
• 42:35
  Speaker 2: I'm sure I'm mispronouncing it. And this one is three
• 42:39
  Speaker 2: hundred kilometers wide, so it's twice as wide as the
• 42:42
  Speaker 2: one that killed the dinosaurs, Oh my gosh. But this
• 42:46
  Speaker 2: one is also much much older. They date this one
• 42:48
  Speaker 2: to like two billion years ago, so when life was
• 42:52
  Speaker 2: very very primitive, and because it's so old, it's been
• 42:56
  Speaker 2: eroded significantly, like mostly it looks like like a partial
• 43:00
  Speaker 2: ring of hills and there's a dome in the middle
• 43:03
  Speaker 2: of it. You have to sort of like squinch your
• 43:05
  Speaker 2: eyes a little bit to even see it.
• 43:07
  Speaker 1: Why is there a dome? Why are rolling hills the
• 43:11
  Speaker 1: sign of an impact crater. I would think that like
• 43:14
  Speaker 1: Ohio being flat would be the sign of an impact crater,
• 43:17
  Speaker 1: But I don't associate hills with impact craters.
• 43:20
  Speaker 2: Yeah, so the dome is really fascinating. When a really
• 43:23
  Speaker 2: big impact or hits the Earth, you don't just get
• 43:25
  Speaker 2: a crater for a huge one, you actually get to
• 43:28
  Speaker 2: bounce back in the center. The Earth is like a
• 43:31
  Speaker 2: big waterbed. Right you hit it, it's gonna bounce back
• 43:34
  Speaker 2: a little bit. And so if it's big enough, you
• 43:36
  Speaker 2: get this bounce back, this dome in the center. And
• 43:39
  Speaker 2: then you also don't just get like one circle. You
• 43:42
  Speaker 2: can have multiple rings. It's like the seismic waves travel
• 43:46
  Speaker 2: through the Earth and they get frozen in several places.
• 43:49
  Speaker 2: It's not actually something that's understood very well. You can
• 43:52
  Speaker 2: see it in a few other places around the Solar System,
• 43:55
  Speaker 2: impact craters with multiple rings around them, but geologists are
• 43:58
  Speaker 2: still trying to understandactly how that happens. But if you
• 44:01
  Speaker 2: look at these sets of hills in South Africa, you
• 44:04
  Speaker 2: can see that there are multiple rings surrounding this dome.
• 44:08
  Speaker 2: So that looks a lot like a huge impact.
• 44:10
  Speaker 1: The bounce back that you're talking about. That that's the
• 44:13
  Speaker 1: like you said, the lake in Tajikastan has like an
• 44:15
  Speaker 1: island in the middle. That's the that's the bounce back
• 44:18
  Speaker 1: that you were talking about. Okay, got it, Yeah exactly.
• 44:22
  Speaker 2: But because it's so old, it's not really complete anymore.
• 44:24
  Speaker 2: Like if you've seen this thing when it was fresh,
• 44:26
  Speaker 2: you probably would see like a big dome in the
• 44:28
  Speaker 2: middle and then complete rings around it, multiple complete rings.
• 44:32
  Speaker 2: But because it's been two billion years since the incident,
• 44:36
  Speaker 2: a lot of those have just eroded away. So now
• 44:38
  Speaker 2: you have incomplete rings of hills, so partial rings of
• 44:42
  Speaker 2: hills around the dome.
• 44:44
  Speaker 1: But the good news is that all of this has
• 44:46
  Speaker 1: happened in the past half the day. Listeners, it's been
• 44:50
  Speaker 1: nice having you here.
• 44:52
  Speaker 2: Sleep well, and then you know, as the listeners mentioned,
• 44:55
  Speaker 2: maybe the most dramatic incident in Earth history was the
• 44:59
  Speaker 2: formation of the moon. Right, we think that the Earth
• 45:01
  Speaker 2: was hit by a proto planet billions and billions of
• 45:04
  Speaker 2: years ago, which essentially obliterated the entire planet, turned the
• 45:08
  Speaker 2: entire surface into lava, which spun out and turned into
• 45:12
  Speaker 2: the Earth and the Moon. So this is probably the
• 45:14
  Speaker 2: most dramatic event in Earth's history, so dramatic that it
• 45:18
  Speaker 2: doesn't even leave an impact crater, right, It just like
• 45:20
  Speaker 2: vaporizes the whole planet. But they actually think that they
• 45:24
  Speaker 2: found in the Earth's core some evidence of this impact.
• 45:29
  Speaker 1: And what is the evidence.
• 45:30
  Speaker 2: They look inside the Earth, you know, to like the
• 45:32
  Speaker 2: lower most mantle, and they find that some chunks of
• 45:35
  Speaker 2: the mantle look a little bit different. It's like a
• 45:37
  Speaker 2: different composition, different density, and they think that what they're
• 45:41
  Speaker 2: seeing there is mantle from the impact or from FEA
• 45:44
  Speaker 2: that made its way down to proto Earth's lower mantle.
• 45:47
  Speaker 2: So basically, like the inner core of our planet is
• 45:50
  Speaker 2: partially from the inner core of this huge impactor.
• 45:54
  Speaker 1: That's incredible.
• 45:55
  Speaker 2: Yeah, So the blobs, the density patterns inside the Earth
• 45:59
  Speaker 2: show this tell tail sign of this crazy cataclysmic impact,
• 46:04
  Speaker 2: even more dramatic than the one that killed the dinosaurs,
• 46:06
  Speaker 2: even more dramatic than this one that left these eroded
• 46:09
  Speaker 2: rings in South Africa.
• 46:10
  Speaker 1: Glad I wasn't there, and I sure do like the mood.
• 46:15
  Speaker 2: And as much as these all seem scary, Kelly, these
• 46:17
  Speaker 2: all were crucial in life turning out the way that
• 46:20
  Speaker 2: it did. Right. If things had happened differently, we wouldn't
• 46:23
  Speaker 2: be here. And so we can say thank you to
• 46:26
  Speaker 2: the solar system for raining death down on other people's
• 46:29
  Speaker 2: ancestors for so many years.
• 46:31
  Speaker 1: Yes, thank you for this past, but never again in
• 46:34
  Speaker 1: the future. Right, there's no risk of this happening, say,
• 46:38
  Speaker 1: I don't know in the next decade or so.
• 46:41
  Speaker 2: There's actually an asteroid that's a few hundred meters across
• 46:44
  Speaker 2: that's likely to make a close pass in April of
• 46:47
  Speaker 2: twenty twenty nine. It's called Apofis, and they predict that
• 46:51
  Speaker 2: it's going to come by Friday the thirteenth in April
• 46:55
  Speaker 2: twenty twenty nine. But it's just supposed to make a
• 46:57
  Speaker 2: clut us.
• 46:59
  Speaker 4: But it's not.
• 47:00
  Speaker 1: It's not coming on Friday the thirteenth, Are you kidding?
• 47:02
  Speaker 2: I am not making that part of that part is real.
• 47:06
  Speaker 2: You gotta wonder what it's like to be that scientist,
• 47:08
  Speaker 2: like predicting the day it's going to be the closest
• 47:10
  Speaker 2: approach and having to be like Friday the thirteenth.
• 47:16
  Speaker 1: Or I wonder if you have like a Cassandra syndrome
• 47:19
  Speaker 1: sort of thing, like, no one's gonna believe me if
• 47:21
  Speaker 1: I say it's coming on Friday the thirteen.
• 47:23
  Speaker 2: That's right.
• 47:24
  Speaker 1: How close is close when you say it's going to
• 47:26
  Speaker 1: make a close pass?
• 47:27
  Speaker 2: You know, astronomically speaking, anything that comes like with between
• 47:31
  Speaker 2: the Earth and the Moon is pretty close. But that
• 47:33
  Speaker 2: doesn't mean it's very dangerous. The Earth is still a
• 47:36
  Speaker 2: very small target compared to the vastness of space, and
• 47:40
  Speaker 2: it's hard to predict these things years out. So as
• 47:42
  Speaker 2: time gets closer, they'll predict it more accurately, and very
• 47:45
  Speaker 2: likely we'll all be fine.
• 47:46
  Speaker 1: But it's like within the range of error right now
• 47:50
  Speaker 1: that Earth could get hit.
• 47:51
  Speaker 2: Depends how generous you want to be with range of error.
• 47:53
  Speaker 2: There's always systematic uncertainties that haven't accounted for that increase
• 47:56
  Speaker 2: the envelope to include the Earth. So yeah, it's possible
• 48:00
  Speaker 2: it could hit the Earth. Maybe we should be thinking
• 48:02
  Speaker 2: about Plan B Kelly, what do you think?
• 48:04
  Speaker 1: I don't know, mostly because I think there's zero chance
• 48:09
  Speaker 1: that we could have a self sustaining settlement on Mars
• 48:11
  Speaker 1: by twenty twenty nine. So if Earth is going to
• 48:14
  Speaker 1: be destroyed in twenty twenty nine. You know, a Mars
• 48:17
  Speaker 1: settlement would just be like a couple years behind. Maybe
• 48:21
  Speaker 1: you'd buy us a couple more years or something, but
• 48:23
  Speaker 1: I doubt it. For more information, check out A City
• 48:26
  Speaker 1: on Mars by Kelly and Zach Widersmith.
• 48:30
  Speaker 2: I mean, if Earth's civilization is going to be destroyed
• 48:31
  Speaker 2: in five years anyway, might as well spend all your
• 48:33
  Speaker 2: money on books right now.
• 48:35
  Speaker 1: That's exactly well, it's a good deal, even if there's
• 48:38
  Speaker 1: not a world ending cataclysm coming.
• 48:42
  Speaker 2: Well, it's fun to think about the crazy history of
• 48:45
  Speaker 2: the Earth. You know. It hasn't just been bubbling oceans
• 48:49
  Speaker 2: and hot tubs and all sorts of cozy times. It's
• 48:51
  Speaker 2: been dramatic and cataclysmic. And we can find the evidence
• 48:55
  Speaker 2: of those impacts on the surface of other objects in
• 48:58
  Speaker 2: the Solar System, but also year on Earth. And I
• 49:01
  Speaker 2: love when geologists unearth the evidence here on Earth for
• 49:05
  Speaker 2: crazy events in our deep history.
• 49:07
  Speaker 1: Way to go, geologists, don't let it happen again.
• 49:13
  Speaker 2: It's on you, exactly. We're counting on you, well, all right,
• 49:19
  Speaker 2: even if we do nothing about it's knowing how this
• 49:21
  Speaker 2: works and knowing the history of the impacts. Maybe you
• 49:24
  Speaker 2: will help us figure out how to prevent them in
• 49:26
  Speaker 2: the future. Thanks very much everybody for listening, and thanks
• 49:29
  Speaker 2: Kelly for joining us today.
• 49:30
  Speaker 1: Thanks for having me on the show. It was quote
• 49:32
  Speaker 1: unquote fun as always.
• 49:37
  Speaker 2: All Right, everyone, tune in next time for more science
• 49:45
  Speaker 2: and curiosity. Come find us on social media where we
• 49:47
  Speaker 2: answer questions and post videos. We're on Twitter, Discord, Instant,
• 49:52
  Speaker 2: and now TikTok. Thanks for listening and remember that Daniel
• 49:55
  Speaker 2: and Jorge Explain the Universe is a production of iHeartRadio.
• 49:59
  Speaker 2: For more podcast from iHeartRadio, visit the iHeartRadio Apple Apple Podcasts,
• 50:04
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